Sudden ph Drop & Fish Die Off

Discussion in 'Pond Archive' started by JB, Jun 18, 2011.

  1. JB

    JB Guest

    I've been a ponder since 1998. I recently experienced something that I
    hadn't before; a fish die off. I lost 4 6-7 inch goldfish in one day and
    then one or two more on the subsequent days. My large Koi seemed fine
    and the small goldfish appeared healthy as well. I've never lost this
    many fish in such a short time for what appeared to be health reasons.
    (Snakes and GBH yes but that's another topic.

    The weekend before I'd cleaned out my Bio-Falls filter, washed off the
    Matala pads, spun plastic filter pads and 4 bags of lava rock and
    bio-balls as I usually do once a year. The water was crystal clear, pond
    was looking good and then the fish began to die. Initially, I took it as
    an unfortunate coincidence and then it continued. Then, I thought that
    it might have been because the daily high temperature had jumped up
    about 20 degrees from what it had been. (What happened to Spring?)

    A friend of mine suggested that I test the water. Me test!? I was beyond
    that. Hadn't done a water test in 3 or 4 years. Things were fine, or so
    I thought. I dug out my box of test kits and began testing: Ammonia - 0.
    Oxygen - great. Ph - 6.0! How'd that happen? At one time years back I'd
    used some Ph Down but I never had to raise the Ph.

    I did a water change and brought it up a little. I did others on the
    following two weeks. Ph is up now and the fish seem fine; no more deaths.

    I used to do water changes but I'd not been doing them as regularly as
    I'd done in the past. I guess I need to do them a little more regularly,
    JB, Jun 18, 2011
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  2. JB

    Chris Hogg Guest

    I'm fairly new to ponding and don't have your experience, but I'm
    surprised at your implication that water at pH 6 was responsible for
    killing your fish. I would have thought that pH 6 was perfectly
    acceptable and safe for them. My goldfish are happy in water at pH 6,
    although I do try and keep it nearer 7 for the sake of the snails
    (their shells don't develop properly if the water is too acid, or so I
    understand). I add crushed limestone to correct it. My immediate
    reaction would be to look elsewhere for the cause.
    Chris Hogg, Jun 21, 2011
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  3. JB


    , Jun 21, 2011
  4. JB

    ~ jan Guest

    Yes, agreed on water changes, always. It usually isn't the pH but your
    buffering (kH) that is used up and the pH swinging wildly stresses the
    fish, water changes, assuming one's source has enough natural buffering,
    keeps the kH up in our ponds. ~ jan
    ~ jan, Jun 24, 2011
  5. JB

    BZTGuy Guest

    High temperatures + recently cleaning filters + no regular water
    changes... very likely the added nutrients from the filter cleaning,
    compiled with the temperature spikes, increased nitrite levels and
    stressed the fish. Can you test for that?

    In any case, do you have any Water Hyacinths in your pond? That will
    help. Also, supplementing with a microbial product designed to
    denitrify the water would be a good, headache-free solution. I can
    help with that if you send me a private message. Another thing you can
    do is fill out our pond survey and it will be submitted to our tech

    Bruce Rich
    BZTGuy, Jun 30, 2011
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